W.J. Weller About Roles Name : W.J. Weller Book Role Computer Arithmetic for the ZX81 User Author Change Request You can request changes or additions here. You can upload files. All change requests are actioned as quickly as possible and you will be informed of the result. Details Files Your Name * Email * Details Your browser doesn't have Flash, Silverlight or HTML5 support. Submit Thank you for your change request. We will respond as soon as possible.